async function loadPerformanceData(startDate, endDate) {
    if (!document.getElementById('totalThroughput')) return;
    
    try {
      console.log('正在加载数据...', startDate, endDate);
      const response = await fetch(`/api/performance?start_date=${startDate}&end_date=${endDate}`);
      const data = await response.json();
      
      console.log('API返回数据:', data);
      
      // 确保数据存在再更新
      updateDeliveryMetrics(data.delivery_stats || {new_requirements: 0, delivered_requirements: 0, throughput_rate: 0});
      updateFTProjectTable(data.ft_projects || []);
      updateDelayedRequirementsTable(data.delayed_requirements || []);
      updateWorkloadTable(data.workload_stats || []);
      
    } catch (error) {
      console.error('加载效能数据失败:', error);
      // 显示错误提示
      alert('数据加载失败，请检查控制台获取详细信息');
    }
  }